devbrain-live

1// devbrain-live — what memory did this session actually move?
2//
3// DevBrain's hooks are deliberately quiet: the briefing goes into the agent's
4// context, the save prompt goes to the agent, the recall after a failing
5// command goes to the agent. None of it is addressed to the person watching, so
6// from the outside a session looks identical whether memory is working or doing
7// nothing at all. That is how it went write-only for two days without anyone
8// noticing.
9//
10// This mod is the dial on the outside of the box. It counts what it can see
11// from tool calls, reads the recall count DevBrain records for the session, and
12// pins one line under the prompt:
13//
14//   DevBrain · 2 saved · 1 already known · 1 recalled
15//
16// It watches, and changes nothing: every hook passes its event straight on.
17
18/** A save through the MCP tool, under any server prefix, or through the CLI. */
19const SAVE_TOOL = /(?:^|__)save_entry$/;
20const SAVE_COMMAND = /\bdevbrain\s+note\b/;
21
22/** Titles saved this session, newest last. */
23let saved = [];
24/** Saves DevBrain rejected as near-duplicates — memory working, not failing. */
25let known = 0;
26/** Past fixes DevBrain volunteered after a failing command. */
27let recalled = 0;
28
29/** True when this tool call is an attempt to record knowledge. */
30function isSaveCall(e) {
31  const tool = typeof e.tool === 'string' ? e.tool : '';
32  if (SAVE_TOOL.test(tool)) return true;
33  return typeof e.command === 'string' && SAVE_COMMAND.test(e.command);
34}
35
36/**
37 * The entry's title, from the MCP argument or from the quoted text of a
38 * `devbrain note` command, with its type prefix and detail trimmed off — the
39 * same "<title> — <detail>" shape the CLI splits on.
40 */
41function savedTitle(e) {
42  if (typeof e.title === 'string' && e.title.trim()) return e.title.trim();
43  const command = typeof e.command === 'string' ? e.command : '';
44  const quoted = command.match(/devbrain\s+note\s+["']([\s\S]+?)["']\s*$/);
45  const body = (quoted ? quoted[1] : '').replace(/^\s*[a-z-]+:\s*/i, '');
46  const dash = body.search(/\s[—–]\s|\s--\s/);
47  return (dash > 10 ? body.slice(0, dash) : body).trim() || 'untitled';
48}
49
50/** Whatever came back, as text we can look for a phrase in. */
51function resultText(value) {
52  if (typeof value === 'string') return value;
53  try {
54    return JSON.stringify(value ?? '');
55  } catch {
56    return '';
57  }
58}
59
60/**
61 * The one line under the prompt.
62 *
63 * It says something even at rest. A counter that is blank until the first save
64 * is indistinguishable from a mod that failed to load, which defeats the point
65 * of having a dial at all.
66 */
67function statusText() {
68  const parts = [];
69  if (saved.length > 0) parts.push(saved.length + ' saved');
70  if (known > 0) parts.push(known + ' already known');
71  if (recalled > 0) parts.push(recalled + ' recalled');
72  return 'DevBrain · ' + (parts.length > 0 ? parts.join(' · ') : 'watching');
73}
74
75/**
76 * How many past fixes DevBrain has volunteered this session.
77 *
78 * DevBrain's PostToolUse hook records every entry it surfaces in the session's
79 * own state file, so the count is read from there rather than guessed at. Any
80 * failure leaves the number out of the line instead of breaking it.
81 */
82async function readRecalled($) {
83  try {
84    const home = (await $.env.get('USERPROFILE')) || (await $.env.get('HOME'));
85    if (!home) return 0;
86    const id = await $.session.id();
87    const text = await $.fs.read(home + '/.devbrain/sessions/' + id + '.json');
88    const state = JSON.parse(typeof text === 'string' ? text : String(text));
89    return Array.isArray(state.surfaced) ? state.surfaced.length : 0;
90  } catch {
91    return 0;
92  }
93}
94
95export function register(on) {
96  on('session.start', async ($, e, next) => {
97    await $.command.register({
98      name: 'devbrain-session',
99      description: 'What DevBrain recorded and recalled this session',
100    });
101    recalled = await readRecalled($);
102    $.ui.status(statusText());
103    return next(e);
104  });
105
106  // Watch every tool call for an attempt to record knowledge. The call itself
107  // is passed straight through — this mod never changes what Claude does.
108  on('tool.call', async ($, e, next) => {
109    if (!isSaveCall(e)) return next(e);
110
111    const title = savedTitle(e);
112    const result = await next(e);
113
114    // A rejected near-duplicate is memory working. Counted apart, so the line
115    // does not read as a failure and does not inflate the saved count.
116    if (/already known/i.test(resultText(result))) {
117      known += 1;
118    } else {
119      saved = [...saved, title];
120      $.ui.toast('DevBrain saved: ' + title);
121    }
122    $.ui.status(statusText());
123    return result;
124  });
125
126  // Recall happens inside DevBrain's own hook, which this mod cannot observe
127  // directly, so the count is refreshed when the turn settles.
128  on('turn.complete', async ($, e, next) => {
129    recalled = await readRecalled($);
130    $.ui.status(statusText());
131    return next(e);
132  });
133
134  on('command.run', { command: 'devbrain-session' }, async () => {
135    if (saved.length === 0 && known === 0 && recalled === 0) {
136      return { text: 'Nothing recorded or recalled yet this session.' };
137    }
138    const lines = saved.map((title, i) => '  ' + (i + 1) + '. ' + title);
139    return {
140      text: [
141        'Saved this session: ' + saved.length,
142        ...lines,
143        known > 0 ? 'Already known, not duplicated: ' + known : '',
144        recalled > 0 ? 'Past fixes recalled after a failing command: ' + recalled : '',
145      ]
146        .filter(Boolean)
147        .join('\n'),
148    };
149  });
150}
151